Operations is actually responsible for implementing IT changes, but change management is accountable to ensure changes are made with minimum disruption to IT Services.

So is it the responsibility of change management to ensure that operations has taken all the necessary precautions to head off any unplanned disruption as a result of a change or does that responsibility sit squarely with operations?

If the former is true, change management will require a signigicantly broader skill set, e.g., have the ability to scrutinize test plans.

1) Opertions ensures that the business can function with its IT architecture

In other words. OPerations makes sure the company can conduct business

2) Change management in operations ensures that any IT work which makes changes to the existing 'production'' environment follows the specific process (chaneg managemnt ( before it is implemented to esnure among other things the impact to the business is either reduced or quantified

3 ) Change managemwent in others areas track the ch'changes'; to their area and make sure they are done in a controlled and processed process_________________John Hardesty
ITSM Manager's Certificate (Red Badge)

Change management is neither a quality control nor scrutiny activity - it is pro-active, not reactive. It is the activity of managing (not performing) changes._________________"Method goes far to prevent trouble in business: for it makes the task easy, hinders confusion, saves abundance of time, and instructs those that have business depending, both what to do and what to hope."
William Penn 1644-1718